Structural & systems · Glossary
Accessory Dwelling Unit
Also called: ADU, granny flat, in-law unit
An Accessory Dwelling Unit (ADU) is a secondary, self-contained dwelling located on the same lot as a primary residence. ADUs include their own kitchen, bathroom, and sleeping area, and can be detached (DADU), attached to the primary home, or converted from existing space such as a garage or basement.
Example
California state law permits ADUs up to 1,200 square feet by-right on most single-family lots.
Why this matters for renovation projects
Accessory Dwelling Unit shows up on permits, contracts, or estimates that Renology covers across LA, San Diego, San Francisco, Seattle, Portland, and Denver. Most homeowners encounter the term once a project is already mid-flight, when there is no time to learn its mechanics without slowing the contractor. Knowing what it means before signing the contract is the difference between a clean project and an avoidable surprise. For how Renology calibrates cost ranges against permit valuations and contractor invoices, see the methodology.